Uncovering the Structure-Property Relationships in Epitaxial Pd Metal and PdO Thin Films

Palladium and other platinum group elements are highly valued for their exceptional physical and catalytic properties, playing pivotal roles in processes such as hydrogenation, carbon monoxide oxidation, and automotive emission control. The study of epitaxial thin films of palladium (Pd) and palladium oxide (PdO) holds significant promise for advancing our understanding of their structure-property relationships and optimizing their catalytic performance. In this talk, I will present our recent effort in the molecular beam epitaxy growth of Pd and PdO thin films, focusing on how controlled defect introduction, phase boundary engineering, and crystallographic orientation can influence their catalytic activities. Through a combination of advanced characterization techniques and theoretical modeling, we investigate the intricate interplay between structural defects and phase transitions in determining the electronic and catalytic properties of these films. We show that the extended defects and deformations associated with them directly affect hydrogen absorption, desorption, and the formation of hydrides upon hydrogen exposure. Further work along this direction will provide the physical principles for the design of PGE materials with tailored catalytic functions.